Rock drilling motor



May 21, 1935. Y M. c. HUFFMAN ROCK DRILLING MOTOR Filed June 25, 1932 we wwu J0 Mfbzmggfw J01,0

Patented May 21, 1935 ROOK DRILLING Moron Mel-vin Chester Huffman, Claremont,-N.rH., assignor to Sullivan Machinery Company, a corporation of Massachusetts Application June 23, 1932, SeriaLNo. 618,924

v 6 Claims.

My invention relates to rock drilling motors, and more particularly to rock drilling motors of the type employed for the drillingfof' fairly deep, dry holes from which it is desired to blow the cuttings.

- An object of my invention is to provide an imn proved drilling motor of the type specified. Anf

V ferred form of my invention is shown for purposes of illustration,-

Fig. l is, in the main, a central longitudinal Y vertical section through a rock drilling motor in which thepreferred embodiment of my invention is incorporated, some parts of the motor being shown in elevation, and the parts being shown in the position for hole blowing.

Fig. 2 is a fragmentary View showing the same 1 motor with the parts in one of the normal running positions.

Fig. 3 is another fragmentary view showing the distributing valve mechanism in a different run'- ning position.

Fig. 4 is an enlarged fragmentary sectional view taken on the plane of Fig. 2, showing the distributing valve'in hole blowing position.

The illustrated form of tool is provided with a cylinder I'which is Aembraced at its rearend i by a head block or casing 2, on which a handle 3, having suitable grasping portions 4, is mounted. At the forward end of the cylinder there is provided a chuck 5 which is` adapted to receive the shank or headof a 4drilling tool 6, the inner end of this shank being positioned to receive blows from a hammer piston 'i which is reciprocable within the cylinder. `The hammer piston is actuated by pressure fluid controlled by a pressure fluid actuated distributing valve 8, which is of the type thrown in one direction by constant pressure and inthe opposite direction by a piston controlled reduced pressure. Thevalve 8 is herein located in alinement with the piston and at the rear end thereof, within a valve` chamber formed in a valve-,block 9 which is seated inthe casing 2.

Between the valve block and the cylinder there is provided a plateplil having a rearwardly projecting boss Il.

Pressure uid is conducted to the tool from any suitable source, through a supply pipe I2 and through a throttling device herein comprising a valve I3, later more fully described, at the rear endof the valve block. At its rear end the valve chamber communicates with a constant pressure chamber I4 to which, through an opening I5, pressure is supplied so long as the throttle Valve I3 is unseated. The communication of the valve chamber with the constant pressure chamberV I 4 is through an opening of reduced cross sectional areaand the valve has a contracted portion I5' slidable in the opening and constantly expose-d to live pressure uid in the constant pressure chamber. The valve chamber is provided also with a constant pressure groove I5, to which `the live pressure fluid is constantly admitted, when the throttle is Open, through one or morelongitudinal passages Il, the latter extending from the groove rearwardly to the space to which the throttle valve admits pressure. In the rear position of the distributing valve, working pressure is conducted from the pressure groove. IB to the forward end of the cylinder to return thepiston, by way of a circumferential valve groove Il', and one or more longitudinally extending passages I8, which open into the forward end of the cylinder through ports I9. In the forward position of the distributing valve, working pressure fluid is conducted to the rear end of the cylinder from the pressure groove I6, through the circumferential valve groove I1 on the distributing Valve, toa valve block groove 20, and thence forwardly through the longitudinal passage or passages 2| tothe rear end of the cylinder. Y Exhaust is eected from the rear end ofthe cylinder when the distributing valve isV in its rearward position, through the passages 2 I, the valve block groove 23, an exhaust Valve-groove 24, an exhaust passage 25, an exhaust space 26 in the member 2, and a terminal exhaust passage 21.' From the forward end of the' cylinder exhaust takes place in part through a bore 28, which is closed by the striking portion 29 ofthe piston, when the latter Ais in forward position, and through the bore of the drill steel, and around the latter; and also, in part, through port IS, passage I8, and passages 30 communicating at their opposite ends with the rear end of the main valve chamber and with the space 26, respectively. When the piston 1 is in its forward position, the reduced portion 29 llsthe opening 28 and prevents the escape of air from the forward end of the cylinder, so that air admitted through the port I 9 will force the piston rearwardly. However, as soon as the portion 29 is withdrawn from the bore 28, the forward end of the piston is connected for a restricted exhaust through the bore 28 and that in the hollow drill steel.

The distributing valve is reciprocated by differential pressure, means being provide-d for intermittently applying pressure uid to the forward or larger area of the Valve to lift it intermittently against the constant pressure in the pressure chamber I4. For this purpose, the valve is constructed in the form of a hollow shell, the interior of which is partially lled by the plug iI, previously mentioned, the latter having a groove or passage 32 formed in its side connecting with an intermittent pressure passage 33. The passage 33 is connected by two ports 34 and 35; opening into the cylinder chamber at different points spaced Yfrom each other longitudinally of the cylinder, with the cylinder bore; the port 34 being substantially in the same transverse plane as a second port 35, which is in constant communication with the constant pressure chamber I4 through a longitudinal passage 3l. When the piston moves forwardly, the port 34' is connected with the constant pressure port 35 by means of a reduced portion 38 on the piston, and the valve is reversed by pressure admitted to the large area thereof from the constant pressure chamber through ports 35', 34V and passage 33. On the other hand, when the piston moves backward,

K pressure fluid is exhausted from the larger area of the valve by the pistons uncovering of the port 35 and connecting the latter to exhaust through the bore 23 and the hollow steel; a sufficient pressure drop following, during normal running,

` the withdrawal of nose 29 from bore 28 to permit constant pressure on the reduced upper end of the valve to overcome the pistonY controlled reduced pressure below the valve.

Through the reciprocation of the distributing valve and the transfer of pressure fluid through the described ports and passages, the hammer piston is caused to move reciprocatively within the cylinder and to deliver its blows against the head of the tool with great rapidity, in a manner which will be obvious from the description given.

' To enable the blowing of the hole being drilled, which may advantageously be accomplished by holding the piston 'I at'the rear end of the cylinder by supplying pressure continuously to the forward end of the cylinder and permitting the pressure t passfrom said forward end through the hollow drill steel, I have provided improved mechanism.

Within a bore 457, extending from end to end of the valve block 9, is reciprocably arranged a manually operable valve member 4I. This valve member has a push button portion 42 which projects through an opening 43 in the member 2 into convenient reach of an operator. It also has a shoulder forming collar 44 movable in an enlarged chamber 45 in the member 2 adjacent the top of block 3 and limiting movement of the valve member 4I in each direction. 'I'he lower end of the bore 4B is in communication, through a recess 46, with the space below and within the Valve member 8.

Valve member 4I has a circumferential groove 4l and also a longitudinally extending bore 4S extending from the lower end of the member to a point high enough to permit communication through a radial port 49 with the groove 4 7,

through which it passes to bore 48 and recess 46 and beneath the valve 8, overcoming the opposing constant pressure and holding the valve in raised position, thereby causing the piston 'I to be maintained continuously in rearward position and Huid to flow to the hollow drill steel from the front end of the cylinder bore. It will f be observed that fluid flows not only by way of II, I5, III-and I9, but also by way of I'I', I5, 4l, 49, 48, 45, 33 and 35 to the forward end of the cylinder, the pressure drop with the port 35 uncovered not being sufficient to permit valve 8 to move to its bottom position so long as the relatively direct supplythrough I5, 4'I, 49, 48 and 46 continues. Y

When the push button 42 is released, the pressure below valve 4I will raise the valve to the position shown in Fig. 3, interrupting communication between groove 4'I and live air groove I6. The distributing valve 8 will then be free to resume normal operation and cause the piston I to resume hammering. A spring may obviously be used below the valve 4I to hold it in top position, if desired, but since the pressure below the valve Il never drops to atmospheric during ruiming of the motor, the valve 8 will be held up Without this added aid.

A suitable hand lever 50 is arranged to open the throttle valve I3 when desired. Of course the lattermust be open during hole blowing.

Extended repetition of the mode of operation is not necessary. 'I'o start the drill motor, the operator depress'es the outer end of lever 55 and moves the throttle valve I 3 to the left and admits air from the bore I 2 to the space I5, and the motor starts To blow the hole, the operator depresses the plunger or push button 42 and moves the valve 4I to the position of Fig. 1, and live air.

then flows from space I through passages I'I to groove I5, then through groove 4l, port 49 and bore 43 to recess 46, and holds Valve 8 in top position. Live air then flows from space I5, through passages I1, groove IB, groove I1', passages I8 and port I9 to the bottom of the cylind'er, and holds piston 'I in the position of Fig. 2, and also flows in part through the hollow steel to blow the hole. Simultaneously with this flow through I8, there is a supplemental ow through 33 as above explained. Release of plunger 42 while the throttle I3 is kept open will cause a re` sumption of hammering.

From the foregoing description, it will be apparent that I have provided an improved drilling apparatus having improved hole blowing means, which is very simple, which provides surety of action by subjecting a large area of the distributing valve to live pressure, which requires a minimum of modification of the familiar type of drill with which it is used, and which is exceedingly convenient to operate.

While I have in this application specifically described one form which my invention may assume in practice, it will be understood that this form is shown for purposes of illustration, and that the invention may be modified and embodied in various other forms without departing from its spirit or the scope of the appended claims.

What I claim as new and desire to secure by Letters Patent is:

1. A pressure fluid motor comprising a cylinder having a bore, a piston therein, a iluid actuated distributing valve controlling the movement of said piston, said valve having an area subjected to constant pressure and a larger opposed area subjected to a piston controlled reduced pressure, a passage connecting said last named area to the cylinder bore, and means for interrupting operation of said valve and normal operation of the piston including means for supplying live pressure fluid to said larger area continuously and thence through said passage to the cylinder bore.

2. A pressure uid motor' comprising a cylinder having a bore, a piston therein, a iiuid'actuated distributing valve controlling the movement of said piston, said valve having an area subjected to constant pressure and a larger opposed area subjected to a piston controlled reduced pressure, a passage connecting said last.

tuated distributing valve controlling the movement of said piston, said valve having an area subjected to constant pressure and a larger opposed area subjected to a piston controlled reduced pressure, a passage controlled by said valve for supplying piston actuating iluid to one end of the cylinder bore, a passage connecting said larger area to the cylinder bore, and means for interrupting operation of said valve and normal operation of the piston including means for supplying live fluid to said larger area continuously and thence through said second named passage to the cylinder bore, pressure fluid continuously flowing through said supply passage to said end of said cylinder bore when operation of said valve is so interrupted.

4. A pressure uid motor comprising a cylinder having a bore, a. piston therein, a fluid actuated distributing valve controlling the movement of said piston, said valve having an area subjected to constant pressure and a larger opposed area subjected to a piston` controlled reduced pressure, a passage connecting said last named area. to the cylinder bore, said passage controlled by said piston and provided to supply pressure fluid from said cylinder to said larger area to throw said valve against the opposing constant pressure, and means for interrupting operation of said valve to hold'said valve in its thrown position against said opposing constant pressure and to hold said piston retracted including means for supplying live uid to said larger area continuously, said passage when said valve is in said thrown position conducting a portion of the uid supplied continuously to said larger area from the latter to the cylinder bore.

5. A `pressure fluid motor comprising a cylinder having a bore, a piston therein, a uid actuated distributing valve controlling the movement of said piston, said valve having an area subjected to constant pressure and a larger opposed area subjected to a piston controlled reduced pressure, a passage connecting said last named area to the cylinder bore, and means for interrupting operation of said valve and interrupting normal piston operation including a hollow, manually operable valve having a longitudinally extending passage for supplying live pressure uid to said larger area continuously and thence through said passage to said cylinder bore.

6. A pressure uid motor comprising a cylinder, a piston therein, a fluid actuated distributing valve controlling the movement of said piston and having an annular groove on its exterior periphery, said valve also having an area sublected to constant pressure and a larger opposed area subjected to a piston controlled reduced pressure, a fluid supply passage, a passage for conducting live pressure uid from said supply passage to the cylinder bore, the groove in said valve when said valve is in one position connecting said passages, and means for interrupting operation of said valve to maintain said passages in constant communication including means for supplying live pressure fluid from said supply passage independently of said valve groove to said larger area continuously.

MERVIN CHESTER HUFFMAN. 

